The invention relates to a gear housing with a gear unit.
Gear housings, in particular with an internal worm gear, having an electric drive motor flanged onto the gear housing and forming a constituent part of wiper systems for motor vehicles are known in a wide variety of designs.
The known gear housings generally comprise two half-shells, namely a housing base body and a housing cover secured to the housing base body, with a ring seal being provided between the housing cover and housing base body to prevent moisture from entering the gear housing. It is known practice to provide screws or rivets to secure the housing cover to the housing base body, in which case the ring seal arranged between the housing cover and housing base body is designed as a flat seal. This method of fastening is laborious and requires a large number of mounting steps to attach the screws or rivets. In another known technique, a housing cover which is formed from plastic and has integrated plastic clip tabs can be secured to the housing base body, with the plastic clip tabs engaging in corresponding latching lugs of the gear housing. The ring seals used in this case are profiled seals having a sealing edge directed toward the housing base body. A disadvantage with this method is that the plastic clips which are used are prone to breaking and the profiled seal is invariably costly and complicated to produce. It is also known to use plastic clips in combination with a seal which has a larger radial extension than the bearing region for the ring seal on the housing base body.
This embodiment is advantageous in that ring seals without a sealing edge, which can be manufactured economically, can be used, but disadvantageous in that the plastic clips are prone to damage and do not always ensure sufficient seal compression. Additionally known is the use of retaining clips made of spring steel, these only being used in combination with profiled seals having a sealing edge, such seals being complicated and costly to produce. In this fastening method, the radial extension of the bearing region on the housing base body for the seal is larger than the radial extension of the ring seal. Consequently, the housing base body, at least in the contact region, must have a large radial extension which is actually not necessary for stability reasons, a situation which considerably increases the use of material and hence the manufacturing costs.